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Monitoring Protein Adsorption with Solid-state Nanopores
Published on: December 2, 2011
Electrical characterization of protein molecules by a solid-state nanopore
Daniel Fologea1, Bradley Ledden, David S McNabb
1Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701.
Applied Physics Letters
|April 9, 2008
Summary
Researchers used silicon nitride nanopores to measure individual protein molecules, determining their charge and size. This method successfully differentiated between bovine serum albumin (BSA) and fibrinogen proteins.
Area of Science:
- Nanotechnology
- Biophysics
- Analytical Chemistry
Background:
- Protein analysis at the single-molecule level is crucial for understanding biological processes.
- Solid-state nanopores offer a promising platform for label-free biomolecule characterization.
- Accurate estimation of protein charge and size is essential for various applications.
Purpose of the Study:
- To investigate the translocation of individual protein molecules through voltage-biased silicon nitride nanopores.
- To develop a method for estimating protein relative charge and size using ionic current blockages.
- To demonstrate the capability of nanopore measurements in distinguishing between different proteins, such as bovine serum albumin (BSA) and fibrinogen.
Main Methods:
- Measuring ionic current blockages during protein translocation through silicon nitride nanopores under voltage bias.
- Analyzing the mean amplitude, duration, and integral of current blockages to infer molecular properties.
- Utilizing pH variation to study changes in bovine serum albumin (BSA) protein charge.
- Employing an improved chemiluminescent analysis to confirm protein passage through nanopores.
- Comparing nanopore measurements of BSA and fibrinogen to assess size discrimination.
Main Results:
- Ionic current blockages were successfully measured and analyzed for individual protein translocations.
- Relative charge and size of protein molecules were estimated at the single-molecule level.
- Changes in BSA protein charge were successfully measured in response to pH variations.
- Confirmation of BSA molecule translocation through nanopores was achieved.
- Distinction between BSA and the larger protein fibrinogen was demonstrated using solid-state nanopore measurements.
Conclusions:
- Solid-state nanopore measurements provide a viable method for single-molecule protein analysis.
- The technique allows for the estimation of protein charge and size, and the detection of charge variations.
- Nanopore analysis can differentiate between proteins of different sizes, such as BSA and fibrinogen.
- This approach holds potential for label-free characterization of biomolecules.
